This invention relates to a method for the restoration of worn or otherwise damaged components by build-up welding, in particular, solid, three-dimensional compressor blades of aircraft engines.
The compressor blades of aircraft engines are subject to considerable erosion in the area of the tip and—if the content of sand in the air is high—also in the area from the tip to the trailing edge. In addition, the leading edge of the compressor blades, in particular, is prone to damage by larger objects (by small stones, for example). Damaged or worn blades can be replaced by new ones if they are separately manufactured and detachably mounted to the compressor disk. This already costly method can, however, not be applied to compressor wheels made in blisk technology where the disk forms an integral part with the blades.
In fact, the possibilities for the repair of the compressor blades are limited. Here, laser powder build-up welding presents itself as one of the few prospects, in particular under the aspect that a mold supporting the weld pool conformally contains the tip area to be restored, allowing the rework effort to be kept low in comparison with free build-up welding. Laser powder build-up welding in a mold is, however, disadvantageous in that the blade can only be restored in a confined tip area of a few millimeters, this being due to recesses limiting the depth of input of the laser beam and the powder in the mold and, further, the complex, three-dimensional blade shape impeding the removal of a longer mold from the repaired blade upon build-up welding.